The Anatomy of Head & Neck BY: DR. Yahya H. Alfarra Faculty of Dentistry, Palestine University

1. The Anatomy of Head & Neck BY: DR. Yahya H. Alfarra Faculty of Dentistry, Palestine University

2. Main Nerves of the Neck • The nerves of head & neck include: 1- cranial nerves 2- cervical nerves 3- cervical sympathetic chain 4- parasympathetic ganglia&nerves

3. I- Cranial nerves These are 12 pairs of nerves that arise inside cranial cavity from the brain & brain stem. they leave the skull through its foramina&fissures . they are numbered & named from befor backwards as follows:

4. 1st olfactory nerve 9th glosspharyngeal n. 2nd optic nerve 10thvagus n. 3rd oculomotor nerve 11thaccessory n. 4th trochlear nerve 12thhypoglossal n. 5th trigeminal nerve 6th abducent nerve 7th facial nerve 8th vestibulo-cochlear nerve

8. Origin: From postero-lateral sulcus of medulla Course & relations in the neck: * It leaves the cranial cavity through jugualr foramen & has 2 sensory ganglion : Sup. Ganglion (in the jugular foramen) Inf. Ganglion (just below jugualr foramen) * the cranial root of accessory nerve joins the inf. Ganglion of vagus just below jugualr foramen 10th Vagus nerve CN X

9. Note: * Vagus nerve pass down the neck within carotid sheath , lying between IJV& ICA AND then between IJV&CCA at root of neck

10. Meningeal branch: innervated meninges ( supplies the dura mater) 2. Auricular branch: supplies part of the external auditory meatus and the skin of medial side of auricle Note : Ear take it’s innervateion From ?? , AB of VN Branches of the vagus nerve in the neck 2 branches arise from sup. Ganglion:

11. Pharyngeal branch:(motor) contains motor fibers derived from the cranial accessory nerve It lies downwards& forwards between I.C.A & E.C.A to share in the formation of the pharyngeal plexus. * pharyngeal plexus contains CN XI , vagus NX , sympathetic trunk. 2 Branches arise from the inferior ganglion

12. Note: The pharyngeal nerve supplies all the muscles of the pharynx EXCEPT the stylopharyngeus(take from CN ? ) & all the muscles of the soft palate EXCEPT the tensor veli palatini !!!! (? CN) LATER IN (oral cavity)

13. 4. Superior laryngeal nerve: CONTAIN: internal branch (innervated(sensory ) sup. Part of larynx) external branch (motor to the cricothyroid muscle of the larynx) 5. Inferior laryngeal nerve (Recurrent laryngeal nerve): (Ant. Laryngeal N.) innervates all the muscles of the larynx except the cricothyroid and is sensory to the inf. Part of larynx.

14. Clinical note : Right RLN: hooks(back) around the subclavian artery Left RLN: hooks around the aortic arch

18. Type: Pure motor fibers Origin: it arises by 2 roots: cranial&spinal . Accessory Nerve (CN XI)

19. 1- the cranial accessory n.: Joins the vagus n. & is distributed with its: Pharyngeal branch : supply all muscles of pharynx Except stylopharyngeus & all Muscles of palate except tensor palati muscle b) Laryngeal branch : Supply the muscles of larynx 2- the spinal accessory n. : Supplies 2 muscles : SCM b) trapezius Branches of the Accessory n.:

22. Origin: from anterolateral sulcus of meddulla and emerges from the hypoglossal canal. Type: purely motor nerve. It supplies all extrinsic & intrinsic muscles of tounge except palatoglossus Ms. ( ?? X CN.) Hypoglossal nerve (CN XII)

23. Branches arising from hypoglossal nerve itself: n. to styloglossus m. N. to genioglossus m. N. to hyoglossus m. N. to all intrinsic m. of tongue Note : 1+2+3 = Extrinsic m. of tongue 4 Branches arising from C1 joining hypoglossal nerve : Meningeal br.(sensory) to dura mater. n. to geniohyoid m. n. to thyrohyoid m. descending branch joins C2,C3 to form ansacervicalis (supplying infrahyiod muscles) Branches

25. NOTE: • 9th + 10th 11th leave skull through jugular foramen while 12th cranial nerve (??)

31. a) Cutaneous branches Cervical plexus (C1- C4) b) Branches to neck muscles c) Phrenic nerve

35. Thank you